Highly Selective and Efficient Electrocatalytic Semihydrogenation of Diphenylacetylene in a PEM Reactor with Pt–Pd Alloy Cathode Catalysts

Abstract

Electric power can be generated from renewable energy sources such as solar and wind, making electrocatalytic hydrogenation an important technology to reduce carbon dioxide emissions in the organic synthesis industry. In the present work, the electrocatalytic semihydrogenation of diphenylacetylene was carried out in a proton exchange membrane (PEM) reactor with carbon-supported Pt, Pd, and Pt–Pd alloy cathode catalysts. Diphenylacetylene introduced into the PEM reactor at less negative potentials underwent electrocatalytic hydrogenation to provide cis-stilbene as a main stereoisomer, with excellent current efficiencies. Among the investigated catalysts, the Pt–Pd alloy with a composition of 1(Pt):99(Pd) was found to be the most suitable for achieving both high cis-stilbene selectivity and a high production rate (partial current density) for cis-stilbene.

Direct Formation of Metal Layer on Anion Exchange Membrane Using Electroless Deposition Process

“…The cell structure of the similar concept is schematically described elsewhere. 27 One of the biggest advantages of the cell is the spring behind the electrode on one side, which allows us to standardize the pressure for the stack of electrodes. The electrolyte for water electrolysis was 1.0 M K 2 CO 3 solution.…”

Investigation of Parameter Control for Electrocatalytic Semihydrogenation in a Proton-Exchange Membrane Reactor Utilizing Bayesian Optimization

“…Therefore, various applications of PEM reactor systems utilizing electrosynthetic processes, such as the reduction of toluenes (Takano et al, 2016;Fukazawa et al, 2018) and alkenes (Ogumi et al, 1981), and asymmetric hydrogenation of α,β-unsaturated acids (Fukazawa et al, 2020), have been reported (Raoult et al, 1984;Jorissen, 1996;Kishi et al, 2020;Fukazawa et al, 2021). In particular, the electrocatalytic hydrogenation of various alkynes in the PEM reactor is noteworthy because it allows for excellent product selectivity (Fukazawa et al, 2019;Nogami et al, 2020). It is worth mentioning that the hydrogenation reaction in the PEM reactor utilizes water as a proton source, enabling the avoidance of explosive hydrogen gas.…”

Electrochemical Proton Reduction over Nickel Foam for Z‐Stereoselective Semihydrogenation/deuteration of Functionalized Alkynes

“…Other nickel complexes or nanoparticles have been reported to be good reduction catalysts, sometimes needing high hydrogen pressure and high temperature, [17–21] or an excess of the reductants, such as NaBH 4 or formic acid [22–26] . Hydrogen obtained from fossil resources can also be replaced by hydrogen produced electrochemically from water [5,27–30] . This approach is particularly important for deuteration reactions, as it allows isotopically labeled compounds, which have applications in medicinal chemistry, to be synthesized simply by using deuterated water solutions, without the need to use deuterium gas cylinders [31,32] .…”